1. Field of the Invention
The present invention relates an image processor for detecting an object from an image taken by a solid-state image sensing device such as CCD, and particularly a face detector using the image processor, which has the capability of detecting a face area as the object from the image taken against the sun, and providing a processed image of the face area with appropriate brightness.
2. Disclosure of the Prior Art
In recent years, a technique of detecting an object such as a human face from an image taken by an image pickup unit has advanced. For example, Japanese Patent Early Publication [kokai] No. 2003-92700 discloses a digital camera comprising an image pickup unit for converting a light signal provided from an image pickup area through an optical system into an image signal, and a face image detector for extracting only a face image from the image signal. To take a good picture of the human face, it is needed to push a shutter release button at an appropriate timing. In this camera, when the face image is extracted by the face image detector, the shutter release button is automatically pushed to carry out photographing. Therefore, it becomes easy to take the good picture even when an operator of the camera is a beginner.
However, when photographing against the sun, there is a case that the detection accuracy of the face image lowers due to a large difference in brightness between the object and the background. In the above-described digital camera, when a brightness of the entire area of the image is lower than a predetermined level, the photographing can be performed by irradiating a strobe light to the object, or adjusting exposure. These countermeasures are useful at the time of photographing, i.e., at the moment that the shutter release button was pushed. However, when the face image is not accurately detected by the face image detector due to poor lighting conditions, there is a fear that the image of a wrong object other than the human face is automatically taken by the image pickup unit.